The NANOSTIM wireless pacemaker is indicated for: 1. Chronic atrial fibrillation with second-degree AV block or bifascicular branch block. 2. Inaugural rhythms with second or third degree AV block or branch block and a low level of physical activity or a low expected life expectancy. 3. Sinus bradycardia with pausasaislated or unexplained syncope with electrophysiological results. Uses: the wireless pacemaker NANOSTIM is a pulse generator designed for bradycardia stimulation that incorporates a battery and electrodes and must be implanted in the right ventricle. Since it is a cordless device, it does not need a connector, stimulation cable or pulse generator pocket. A non-retractable distal helix with a single twist fixes the device to the endocardium. In addition, three sutures in the outer part of the head of the device offer a secondary fixation. Detection and stimulation occur between a distal electrode near the helix and the external housing of the device. The proximal end of the device has a mechanism that allows coupling it to the decolocation and extraction catheters for repositioning and extraction. The device is communicated bidirectionally with the programmer by electrical signals that are processed between the electrodes of the implanted device and the skin electrodes attached to the patient's chest and connected to the programmer. Accordingly, the device transmits signals by circuits and electrodes previously designed for stimulation, with data encoded by pulses during the refractory period of the heart. The device detects the blood temperature of the right ventricle and increases the frequency of stimulation as the metabolic requirement increases.